﻿/******************************************************************************
 * Spine Runtimes License Agreement
 * Last updated May 1, 2019. Replaces all prior versions.
 *
 * Copyright (c) 2013-2019, Esoteric Software LLC
 *
 * Integration of the Spine Runtimes into software or otherwise creating
 * derivative works of the Spine Runtimes is permitted under the terms and
 * conditions of Section 2 of the Spine Editor License Agreement:
 * http://esotericsoftware.com/spine-editor-license
 *
 * Otherwise, it is permitted to integrate the Spine Runtimes into software
 * or otherwise create derivative works of the Spine Runtimes (collectively,
 * "Products"), provided that each user of the Products must obtain their own
 * Spine Editor license and redistribution of the Products in any form must
 * include this license and copyright notice.
 *
 * THIS SOFTWARE IS PROVIDED BY ESOTERIC SOFTWARE LLC "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
 * NO EVENT SHALL ESOTERIC SOFTWARE LLC BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, BUSINESS
 * INTERRUPTION, OR LOSS OF USE, DATA, OR PROFITS) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *****************************************************************************/

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Spine
{
    public interface IVertexEffect
    {
        void Begin(Skeleton skeleton);
        void Transform(ref VertexPositionColorTextureColor vertex);
        void End();
    }

    public class JitterEffect : IVertexEffect
    {
        public float JitterX { get; set; }
        public float JitterY { get; set; }

        public JitterEffect(float jitterX, float jitterY)
        {
            JitterX = jitterX;
            JitterY = jitterY;
        }

        public void Begin(Skeleton skeleton)
        {
        }

        public void End()
        {
        }

        public void Transform(ref VertexPositionColorTextureColor vertex)
        {
            vertex.X += MathUtils.RandomTriangle(-JitterX, JitterY);
            vertex.Y += MathUtils.RandomTriangle(-JitterX, JitterY);
        }
    }

    public class SwirlEffect : IVertexEffect
    {
        private float worldX, worldY, angle;

        public float Radius { get; set; }
        public float Angle { get { return angle; } set { angle = value * MathUtils.DegRad; } }
        public float CenterX { get; set; }
        public float CenterY { get; set; }
        public IInterpolation Interpolation { get; set; }

        public SwirlEffect(float radius)
        {
            Radius = radius;
            Interpolation = IInterpolation.Pow2;
        }

        public void Begin(Skeleton skeleton)
        {
            worldX = skeleton.X + CenterX;
            worldY = skeleton.Y + CenterY;
        }

        public void End()
        {
        }

        public void Transform(ref VertexPositionColorTextureColor vertex)
        {
            float x = vertex.X - worldX;
            float y = vertex.Y - worldY;
            float dist = (float)Math.Sqrt(x * x + y * y);
            if (dist < Radius)
            {
                float theta = Interpolation.Apply(0, angle, (Radius - dist) / Radius);
                float cos = MathUtils.Cos(theta), sin = MathUtils.Sin(theta);
                vertex.X = cos * x - sin * y + worldX;
                vertex.Y = sin * x + cos * y + worldY;
            }
        }
    }
}
